Resin composition for golf balls

Abstract

The invention provides a golf ball resin composition that includes (A) an aromatic vinyl elastomer and (B) a polyurethane or a polyurea, the amount of component (A) being 50 parts by weight or less per 100 parts by weight of component (B), and also provides a golf ball in which at least one cover layer is formed of this resin composition. The resin composition is particularly useful as a golf ball cover material because golf balls in which it is used do not fly too far and have a good controllability on approach shots, and moreover maintain a good scuff resistance and moldability without a loss of distance on shots with a driver.

1 . A golf ball resin composition comprising:
 (A) an aromatic vinyl elastomer, and   (B) a polyurethane or a polyurea,   wherein the amount of component (A) is 50 parts by weight or less per 100 parts by weight of component (B).   
     
     
         2 . The resin composition of  claim 1 , wherein component (A) is a hydrogenated aromatic vinyl elastomer. 
     
     
         3 . The resin composition of  claim 1 , wherein component (A) is an elastomer obtained by hydrogenating a polymer comprising a polymer block composed primarily of an aromatic vinyl compound and a random copolymer block consisting of an aromatic vinyl compound and a conjugated diene compound. 
     
     
         4 . The resin composition of  claim 1 , wherein component (A) is a hydrogenated aromatic vinyl elastomer obtained by hydrogenating a polymer comprising, at both ends thereof, a polymer block consisting of styrene and, in between, a random copolymer block consisting of styrene and butadiene. 
     
     
         5 . The resin composition of  claim 1 , wherein component (A) has a rebound resilience, as measured according to JIS-K 6255, of 40% or less. 
     
     
         6 . The resin composition of  claim 1 , wherein component (A) has a glass transition temperature (Tg), as indicated by the tan 6 peak temperature obtained by dynamic viscoelasticity measurement with a dynamic mechanical analyzer (DMA), of from −20 to 50° C. 
     
     
         7 . The resin composition of  claim 1 , wherein component (A) has a styrene component content of at least 30 wt %. 
     
     
         8 . The resin composition of  claim 1 , wherein the polyurethane serving as the main component of the composition is an ether-based thermoplastic polyurethane. 
     
     
         9 . The resin composition of  claim 1 , wherein the resin composition has a rebound resilience, as measured according to JIS-K 6255, of 65% or less. 
     
     
         10 . A golf ball comprising a core encased by a cover of one or more layer, wherein at least one layer of the cover is formed of the resin composition of  claim 1 .